Cold sores - painful sores on the lips and around the mouth, caused by a virus
Canker sores - painful sores in the mouth, caused by bacteria or viruses
Thrush - a yeast infection that causes white patches in your mouth
Leukoplakia - white patches of excess cell growth on the cheeks, gums or tongue, common in smokers
Dry mouth - a lack of enough saliva, caused by some medicines and certain diseases
Gum or tooth problems
Bad breath
